The invention relates to a method and device for calibrating sensors, which sensors are e.g. to be used for detecting a substance in a fluid and are integrated on semiconductor chips. In a particularly advantageous embodiment, the invention relates to the calibration of sensors measuring humidity in gases.
One known type of humidity sensors uses a layer of a humidity sensitive material arranged on a semiconductor chip, as it is described in WO 01/42776. Other types of sensors e.g. use metal oxide technologies and be adapted to measure various types of substances in gases or liquids. Typical substances that can be measured are e.g. CO, CO2, NOx, volatile organic compounds (VOC), in particular any type of gaseous organic compounds, and any other types of compound.
Semiconductor chips are usually manufactured in wafers, where each wafer may comprise hundreds or more chips. After manufacturing, the wafers are cut to separate the chips, the chips are placed in a suitable housing and are then calibrated by exposure to fluids of known composition, as it is e.g. described in WO 01/40784.
However, manufacturing a large number of sensors in this manner is cumbersome and expensive.